It is a trend to increase the storage capacity of a magnetic recording apparatus such as a hard disk drive (HDD) has been expanding, and the vertical recording method is coming into practical use as a recording method.
In this vertical recording method, recording is performed by magnetization in the direction perpendicular to the surface of a recording layer of a magnetic recording medium. This method provides high-density recording. In the vertical recording method, however, for the recording density of 100 Gbit/inch2 or higher, the adjacent track gets magnetized by the side fringing occurring on the side surfaces of the magnetic head, with the result that write or read error will occur.
To solve this problem, a so-called a discrete track medium (hereinafter referred to as “DT medium”) has been proposed, wherein the tracks are physically separated from each other by non-magnetic areas (non-recording areas) in which data writing is impossible (Patent Document 1 and Patent Document 2). This DT medium has a non-magnetic area (non-recording area) provided between the tracks, and successfully solves the following problems inherent to the magnetic recording medium capable of high-density recording. Data is written accidentally in the adjacent track. Data is read out accidentally from the adjacent track at the time of reproduction. The output is reduced due to the signal noise produced by the magnetic curvature of the recording bit end portion.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 5-28488
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2005-293633